If we are to start with solids, that will lead to a whole other thread full of questions!
Yes it will, but there is another forum for that
That is a large volume for sure but not unheard of... the fact that she is now waking twice makes me think it might be time for some solids for sure.. at 6 months, she can start them
Of course, with food intolerances, you could be in for quite the process and it's not likely that much is going to be offered that will fill her more than her formula.
Why did the GI have you reduce her feeds? Was she vomiting after most feeds?